For various surgical procedures, and most commonly for coronary artery bypass grafting (CABG), it is common to remove or "harvest" a vascular conduit, such as an artery or vein, from its natural location in a patient's body and to use it elsewhere in the body. In CABG surgery, the vascular conduit is used to establish a bypass between an arterial blood source and the coronary artery being bypassed. Often, one or more of the saphenous veins in the legs are used as the vascular conduit, and is sometimes preferred by some surgeons in emergency situations, and where multiple bypass vessels are needed. Alternatively, an artery proximate the heart, such as the one of internal mammary arteries, can be used as the bypass conduit. Use of arteries rather than veins for a CABG procedure may be preferable as arteries tend to have better patency rates, and require only one anastomotic connection rather than two. For patient's requiring multiple bypasses, a surgeon may use the saphenous vein and in addition to various arteries to revascularize a patient's heart.
The conventional surgical procedure used to harvest the saphenous vein prior to its use, in a CABG procedure for example, may be very traumatic to the patient. The procedure involves making a continuous incision in the leg for the full length of the vein section to be removed in order to provide adequate exposure for visualizing the vein and for introducing tools to sever, cauterize, or ligate the branches of the vein. The incision must then be closed by suturing or stapling along its length. Major complications of the large wound such as skin loss or infections result in significant morbidity for approximately 1% of patients and frequently cause prolonged hospitalization. Other complications, such as impaired wound healing, saphenous nerve damage, hematomas, prolonged lymphatic drainage, fat necrosis with cellulitis, and chronic edema, can occur at rates exceeding 20% and are particularly costly and traumatic for a patient who has also undergone cardiac surgery. Moreover, many patients who do not suffer major complications still experience lower extremity discomfort lasting 4-6 months after the harvesting procedure. Also, ischemic and/or mechanical injury to the saphenous vein during the harvesting procedure may lead to increased rates of occlusion in the vessel graft in the months and years after the procedure. This harvesting procedure also leaves disfiguring scars, increases recovery time and the patient's hospital stay, and adds to the cost of the coronary artery surgery.
In an attempt to overcome these problems, less-invasive techniques for harvesting vessels have been developed. Most current, less-invasive techniques for dissecting a vessel employ a couple of small incisions, one at each end of the section of vessel to be removed. Blunt mechanical force is applied to first create a working space in the tissue surrounding the vein, followed by introducing tools to separate the vein from the surrounding tissue and to clip, cut, and/or cauterize side branches of the vessel. An endoscope is not necessarily required for such a procedure but may be used to enhance visualization of the vessel and the surrounding tissue and work space without having to unduly stretch the patient's skin and tissue to visualize the working space at a distance from the incision.
Even where these less invasive techniques reduce the overall length of the incision, the trauma to the vessel, the surrounding tissue, and the patient can be severe. In particular, the harvesting procedure itself may actually be lengthened and the trauma to the vessel potentially increased due to the number of tools that are needed for the harvesting procedure and which are repeatedly introduced through the incision.
The goal of the present invention is to further reduce the trauma to the patient by providing the capability to more rapidly and less traumatically harvest the vein by detaching the vein from surrounding tissue on all sides in a more expeditious procedure, minimizing the number of tools required for the procedure, and providing an harvesting device and procedure that can be effectively used and performed by a single user, while minimizing the length and number of incisions made.